1. Field of Invention
The current invention includes an apparatus and a method for creating a pressure pulse within drilling fluid that is generated by selectively activating solenoids that initiate flow driven bi-directional pulses. Features of the device include operating a pulser bell within a specially designed annular flow channel designed to reduce turbulent flow of the drilling fluid in a measurement-while-drilling device to provide for reproducible pressure pulses that are translated into relatively noise-free signals. The pulse is then received “up hole” as a series of signals that represent pressure variations which may be interpreted as gamma ray counts per second, azimuth, etc. by oilfield engineers and managers to recognize how to increase yield in oilfield operations.
Current purser technology includes pursers that are sensitive to different fluid pump down hole pressures, and flow rates, and require field adjustments to pulse properly so that meaningful signals from these pulses can be received by a programmable controller.
Additional advantages of the present invention are that it remains insensitive to fluid flow rate or pressure, does not require field adjustment, and is capable of creating recognizable, repeatable, reproducible, clean (i.e. noise free) fluid pulse signals using minimum power due to a unique pulser bell and lower inner flow channel design thereby also eliminating the need for drilling preparation, a field engineer at the well site continuously, and downtime expenses. The annular flow channel is specifically designed such that primarily laminar flow exists in the area where the pulse occurs, thereby providing frequent essentially noise-free pulses and subsequent noise-free signals. Additional pulsers with varying pressure amplitudes are easily added to enable an exponential increase in the bit rate that is sent uphole. This will also allow the addition of more downhole sensors without losing formation resolution.
2. Description of Prior Art
The present invention discloses a novel device for creating pulses in drilling fluid media flowing through a drill string. Devices currently in use require springs or solenoids to assist in creating pulses and are primarily located in the main drilling fluid flow channel. Current devices also require onsite adjustment of the pulser according to the flow volume and fluid pressure and require higher energy consumption due to resistance of the fluid flow as it flows downward in the drill collar. The present inventive apparatus and assembly is also supported by a rigid centralizer facing the direction of fluid flow. The centralizer provides support for the assembly. The pulser assembly includes a fishing head and fluid screen assembly attachment at the top end facing the flow.
The device provided by the current invention allows for the use of a pulser bell that moves from an initial position to an intermediate and final position in both the upward and downward direction corresponding to the direction of the fluid flow. The present invention avoids the use of springs, the use of which are described in the following patents which are also herewith incorporated by reference in U.S. Pat. Nos. 3,958,217, 4,901,290, and 5,040,155. The present invention uses at least two solenoids and simple connecting channels in specific angular positions to provide for enhanced pressure pulses. The design of the present invention allows for a smaller overall annular flow channel thereby allowing for laminar-like flow which also provides for a higher sampling (bit) rate, improved data analysis, less energy consumption and greater reliability.
U.S. Pat. No. 5,040,155 to Feld, et. al. describe a double guided fluid pulse valve that is placed within a tube casing making the valve independent of movement of the main valve body and free of fluctuations of the main valve body. The valve contains a pressure chamber with upwardly angled passages for fluid flow between the pressure chamber and the main valve body. Double guides ensure valve reliability in the horizontal position.
U.S. Pat. No. 5,473,579 to Jeter, et. al., describes a pulser that utilizes a servo valve and spring acting upon each other to urge a signal valve to move axially within a bore with signal assistance coming from a counter balance compensator device.
U.S. Pat. No. 5,117,398 to Jeter describes a pulser device that uses electromagnetically opened latches that mechanically hold the valve in the closed or open position, not allowing movement, until a signal is received and the latches are electronically released.
U.S. Pat. No. 6,002,643 by Tchakarov, et al., describes a pulser device in which a bi-directional solenoid contains a first and second coil and a rod extending within the coils used to actuate a poppet valve creating bi-directional pressure pulses. Orifices to permit the flow of drilling fluid to be acted upon by the piston assembly within the main body of the pulser tool and a pressure actuated switch to enable the electronics of the control device to act upon the pulser tool.
U.S. Pat. No. 4,742,498 to Barron describes a pulser device that has the piston that is acted upon by the drilling fluid and is allowed seating and unseating movement by use of springs and an omni directional solenoid.
U.S. Pat. No. 6,016,288 to Frith discloses a servo driven pulser which actuates a screw shaft which turns and provides linear motion of the valve assembly. All components except the shaft are within a sealed compartment and do not come in contact with the drilling fluid.
U.S. Pat. No. 5,802,011 to Winters, et al., that describes a solenoid driven device that pivots a valve that enters and leaves the annular drilling fluid flow blocking and unblocking the fluid flow intermittently.
U.S. Pat. No. 5,103,430 to Jeter, et al., describes a two chamber pulse generating device that creates fluid chambers above and below a poppet valve that is servo driven. Pressure differential is detected on either side of the poppet through a third chamber and the servo is urged to move the poppet in order to stabilize the pressure differential.
U.S. Pat. No. 5,901,113 to Masak, et al., describes a measurement while drilling tool that utilizes inverse seismic profiling for identifying geologic formations. A seismic signal generator is placed near the drill bit and the generated known signals are acted upon by the geologic formations and then read by a receiver array.
U.S. Pat. No. 6,583,621 B2 to Prammer, et al., describes a magnetic resonance imaging device comprising of a permanent magnet set within a drill string that generates a magnetic flux to a sending antennae that is interpreted up hole.
U.S. Pat. No. 5,517,464 to Lerner, et al., describes a pulse generating device utilizing a flow driven turbine and modulator rotor that when rotated creates pressure pulses.
U.S. Pat. No. 5,467,832 to Orban, et al., describes a method for generating directional downhole electromagnetic or sonic vibrations that can be read up hole utilizing generated pressure pulses.
U.S. Pat. No. 5,461,230 to Winemiller, describes a method and apparatus for providing temperature compensation in gamma radiation detectors in measurement while drilling devices.
U.S. Pat. No. 5,402,068 to Meador, et. al., describes a signal generating device that is successively energized to generate a known electromagnetic signal which is acted upon by the surrounding environment. Changes to the known signal are interpreted as geological information and acted upon accordingly.
U.S. Pat. No. 5,250,806 to Rhein-Knudsen, et al., describes a device wherein the gamma radiation detectors are placed on the outside of the MWD device to physically locate them nearer to the drill collar in order to minimize signal distortion.
U.S. Pat. No. 5,804,820 to Evans, et al., describes a high energy neutron accelerator used to irradiate surrounding formations that can be read by gamma radiation detectors and processed through various statistical methods for interpretation.
U.S. Pat. No. 6,057,784 to Schaaf, et al., describes a measurement while drilling module that can be placed between the drill motor and the drill bit situating the device closer to the drill bit to provide more accurate geological information.
U.S. Pat. No. 6,220,371 B1 to Sharma, et al., describes a downhole sensor array that systematically samples material (fluid) in the drill collar and stores the information electronically for later retrieval and interpretation. This information may be transmitted in real time via telemetry or other means of communication.
U.S. Pat. No. 6,300,624 B1 to Yoo, et al., describes a stationary detection tool that provides azimuth data, via radiation detection, regarding the location of the tool.
U.S. Pat. No. 5,134,285 to Perry, et al., describes a measurement while drilling tool that incorporates specific longitudinally aligned gamma ray detectors and a gamma ray source.
U.S. Application No. 2004/0089475 A1 to Kruspe, et. al., describes a measurement while drilling device that is hollow in the center allowing for the drilling shaft to rotate within while being secured to the drill collar. The decoupling of the device from the drill shaft provides for a minimal vibration location for improved sensing.
U.S. Pat. No. 6,714,138 B1 to Turner, et. al., describes a pulse generating device which incorporates the use of rotor vanes sequentially moved so that the flow of the drilling fluid is restricted so as to generate pressure pulses of known amplitude and duration.
G.B. Application No.2157345 A to Scott, describes a mud pulse telemetry tool which utilizes a solenoid to reciprocally move a needle valve to restrict the flow of drilling fluid in a drill collar generating a pressure pulse.
International Application Number WO 2004/044369 A2 to Chemali, et. al., describes a method of determining the presence of oil and water in various concentrations and adjusting drilling direction to constantly maintain the desired oil and water content in the drill string by use of measuring fluid pressure. The fluid pressure baseline is established and the desired pressure value is calculated, measured and monitored.
International Publication Number WO 00/57211 to Schultz, et. al., describes a gamma ray detection method incorporating the use of four gamma ray sondes to detect gamma rays from four distinct areas surrounding a bore hole.
European Patent Application Publication Number 0 681 090 A2 to Lerner, et. al., describes a turbine and rotor capable of restricting and unrestricting the fluid flow in a bore hole thereby generating pressure pulses.
European Patent Specification Publication Number EP 0 781 422 B1 to Loomis, et. al. describes utilizing a three neutron accelerator and three detectors sensitive to specific elements and recording device to capture the information from the three detectors.